Traditionally, a sliding member, comprising a copper-based alloy bonded on a steel plate, has been frequently used. In such a sliding member, it is necessary to extract a desired shape from the steel plate so that occurred remnants cannot contribute to a product. On the other hand, for the sliding member without extraction, it has proposed for a bearing to form an outer layer with an iron-based sintered compact and form an inner layer with a copper-based sintered compact. (Refer to, for example, Patent Document 1.)
In addition, it is a well-known technology heretofore to form a concave portion on a surface of the sliding member with a blast process and it is a known technology to form an oil reservoir on the surface of the sliding member with the blast process. (Refer to, for example, Patent Document 2).